An RFID tag can be used in security access cards, employee ID cards, automatic toll-paying devices and ski-lift tickets.
RFID enables storage and remote retrieval of data using a device called a RFID tag or transponder. Such a RFID tag has an antenna to enable it to receive and respond to radio frequency queries from a RFID interrogator.
The RFID tag contains a transponder with a digital memory chip that stores a unique code and also possibly other data. The RFID interrogator emits an activation signal that activates the RFID tag in order that the RFID interrogator can read and/or write data to the RFID tag. When an RFID tag passes into a sensing zone of the RFID interrogator, the RFID tag detects the reader's activation signal. The RFID interrogator decodes data from the RFID tag's integrated circuit.
A RFID tag transmits a response signal to a RFID interrogator when it receives a predetermined interrogation signal from the interrogator. This interrogation signal is a specific command at a predefined frequency having a defined data protocol and encoding scheme. When an RFID tag is interrogated, the response signal transmitted by the RFID tag is used by an application driving the RFID interrogator to authorise an action.
However, there is no verification that the bearer of the RFID tag is the person authorised to use the RFID tag. The identity of the bearer cannot be proven by mere possession of the RFID tag. For example, the RFID tag may have been stolen or lost and in the possession of a person other than the person authorised to use the RFID tag.